The processing of filaments of synthetic fibers, such as for example, PET, PP, PA and the like made by a melt spinning method typically includes the steps: ##STR1## and the processing of staple fibers is: spinning.fwdarw.drawing.fwdarw.heatsetting.fwdarw.crimping.fwdarw.drying.f wdarw.cutting to staple fiber
In general, for synthetic leathers to have a genuine leather-like soft surface touch, a titer thereof should be at least below 0.4 d. However, fibers of 0.4 d or less can not be produced by a conventional spinning method mentioned above. Even if fibers below 0.4 d can be produced it is difficult to process them by the application of weaving. There are many types of conjugated fibers. FIG. 1A is a cross-sectional view of conjugated fibers produced by Kanebo, Japan, FIG. 1B is a cross-sectional view of conjugated fibers produced by Teijin, Japan, and FIG. 1C is a cross-sectional view of conjugated fibers produced by Toray, Japan.
Conjugated fibers of each of FIGS. 1A and 1B are of matrix types and are made by conjugated spinning of two different kinds of polymer. But these two types can be put to the production of flat yarns only and they can not be used in false twisting. If they are used in false twisting, it is easy for them to split, said this results fluff and in difficulty in weaving. The conjugated fibers of FIG. 1C is of a sea and islands type, and is also made by conjugated spinning of two different kinds of polymers. The sea component should be completely dissolved to obtain the finer ingredient fibers of island. Because to the sea component should be dissolved completely, the cost is increased.